First, a Little Something From the Chef . . .; . . .Very, Very Little

ALL systems were go. The dab of duck tartare was resting attractively on the world's smallest taro chip, surrounded by a bright-green splash of pureed scallion and accented by a discreet racing stripe of pineapple ketchup off to the side.

Now came crunch time. Normand Laprise, the executive chef at Cena, hunched over the plate and lowered into position a blazing yellow marigold blossom no larger than a dime.

The duck disappeared in its shadow.

''I'm not sure the flower works,'' Mr. Laprise said, taking half a step back to eyeball the situation.

With a deft pincer movement, he extracted a single petal, no larger than a match head, and placed it beside the duck tartare. Perfect. Another amuse-bouche, Laprise-style, rolled off the assembly line.

The predinner treat known as an amuse-bouche, or amuse-gueule, used to be a throwaway, a complimentary ''palate pleaser,'' to translate the term, which was put before the diner to make a good impression. Recently, however, like a bit player with big ideas, it has begun to hog the stage.

All over New York, top chefs are turning the spotlight on their predinner treats, adding layer upon layer of complexity to their tiny offerings, refining and miniaturizing until they achieve one-bite tours de force -- little works of art that in a few cases are approaching the vanishing point.

Some chefs are giving them a permanent place on the menu. At Union Pacific, where diners can already order plates of three to six amuses, Rocco DiSpirito, the executive chef, just introduced a Lilliputian feast he calls 21 Little Tastes -- seven flights of three thematically linked amuses, priced at $135.

There are pastry chefs who have even begun sending out sweet little nothings to tables being cleared for the dessert course. It's the sweet before the main sweet, not to be confused with the petit fours that come after the dessert.

The new-wave amuses are anything but afterthoughts, although they often make use of bits and pieces left over from the entrees.

''It's not like a party hors d'oeuvre,'' Mr. DiSpirito said. ''There are a lot of flavor levels.''

Yes. When Mr. DiSpirito puts together an amuse-bouche, simplicity is not uppermost on his mind. One of his more modest creations begins with a miniature strawberry known as a Tristar, which he cuts into three pieces, outfits with a split fava bean and tops with bits of chopped strawberry, strawberry vinegar, strawberry syrup, aged balsamic vinegar, apricot-kernel oil and bits of apricot kernel.

Another amuse-bouche he calls the ''mini rabbit'' has 20 flavor components.

There's a whiff of the mad scientist about Mr. DiSpirito that is lacking in Mr. Laprise, a Quebecer who implies that he simply throws his amuse-bouche together from little scraps of this or that, depending on what he finds in the refrigerator. ''To me it's a way to play with the maximum of flavor in the smallest possible format,'' he said. Searching for the English word to describe his predinner offerings, he falters, then comes up with ''clin d'oeil'' -- a wink.

That's how fast they go by. Mr. Laprise likes to work small, about the size of a quarter. He mixes together morsels of lobster-claw meat with sliced shallots marinated in grapeseed oil and a touch of cinnamon, corn and fresh chervil, then presses the ingredients into a plastic napkin ring to form an inch-high cylinder, which he tops with avocado. He lays a dainty fingerling potato chip on top, installs a lobster antenna for effect and then squirts a few Zorro Z's of reduced red bell pepper juice on a preposterously large plate. You don't know whether to pin the thing on your lapel or eat it.

Not everyone has signed on to the program. At Patroon, Geoffrey Zakarian serves two-bite amuses with simple, straighforward flavors. Last week, for example, he sent out spinach in a Gruyere-flavor puff pastry and tuna tartare with fresh beets and cherries.

''I like three or four ingredients, period, and I don't like them too small,'' he said. ''When it's one tiny bit of food on one tine of a fork -- it's gone and you say, 'What was that?' ''

The preappetizer appetizer is an arriviste, dating back no further than the advent of nouvelle cuisine in the early 1970's. The term itself first popped up in ''Les Grandes Vacances'' (''The Long Holiday''), a 1946 novel by Francis Ambriere, where ''amuse-gueule'' (pronounced ah-MOOZ GOOL) was used to mean a miniature snack that cheated hunger pangs. Since ''gueule'' has a mildly slangy, coarse sound in French, amuse-gueule quickly generated a nicer-sounding synonym, amuse-bouche (ah-MOOZ BOOSH). The difference is approximately the same as that between ''toilet paper'' and ''toilet tissue.''

''At a brasserie or bistro, you would use 'amuse-gueule,' and at a nice restaurant you would use 'amuse-bouche,' '' said Xavier Le Roux, a lecturing instructor at the Culinary Institute of America and the chef at its Escoffier Restaurant.

''The amuse was a way to tease the appetite and to get people into the ambiance,'' he added. ''Also, nouvelle portions were much smaller than normal, so it was an extra bite.'' In nouvelle's overheated, highly competitive environment, the amuse was also one more way to make an impression and to top the competition.

''We never served an amuse-bouche at Le Pavillon,'' said Jacques Pepin. The restaurant turned out canapes and miniature hors d'oeuvres by the hundreds for cocktail parties and receptions, but at dinner -- nothing. To this day, the culinary schools offer no instruction on the theory and practice of the amuse, restricting themselves to classes on canapes and hors d'oeuvres.

The amuse-bouche concept made its way across the Atlantic fairly quickly, although restaurants tended to limit their amuses to one signature dish that could be prepared well in advance. During the mid-1970's and 80's, diners at the Quilted Giraffe were presented with a smoked salmon and foie gras ''cake'' in seven layers, with the foie gras whipped into a kind of frosting.

''There was always this issue: Could the amuse-bouche be warm and cooked to order, or did it have to be cold?'' said Barry Wine, who was the restaurant's chef and owner.

Clearly, these were early days, an eon removed from 21 Little Tastes.

Why the fuss and bother over a bit of food that disappears in one quick bite? The answer is a mixture of art and commerce. Chefs love the amuse-bouche because it gives them the chance to execute a quick, virtuosic turn.

''It's the only fully creative outlet you have, the only completely free thing you can do,'' Mr. DiSpirito said. ''It also lets me expand the menu without actually expanding the menu.''

There are other advantages. An amuse-bouche can be a trial balloon. If customers respond with wild enthusiasm, yesterday's amuse can become tomorrow's appetizer. The amuse also allows chefs to use fresh ingredients that turn up at local markets in small quantities. It buys time for a kitchen rushing to fill the appetizer orders.

For restaurant owners, the amuse-bouche works as a customer-pleaser, and it sets up a wine purchase beautifully. It also implies a certain level of quality and service, which is why the amuse is showing up even at modest-price restaurants like Aquagrill, where customers get a small dollop of salmon tartare on a potato gaufrette with their aperitif.

''At a restaurant like mine, which has two stars, you feel like you're getting a three-star experience,'' said Jeremy Marshall, Aquagrill's chef and owner.

Pastry chefs have seen the busy fingers at work and have drawn their own conclusions. Claudia Fleming, the pastry chef at Gramercy Tavern, began sending out tiny fruit tarts and dinky creme brulees after watching Tom Collichio, the executive chef, work on his amuse-bouches. With time, she has developed more ambitious amuses like tiny apricot tart tatins with black-pepper ice cream, or warm blackberry compotes with sweet-corn ice cream.

''These are slightly obscure things that I could not sell on the menu,'' she said. ''It's just a couple of bites, a titillation. I don't want to say I've gotten carried away, but I have gotten very passionate about them.''

At the same time, Ms. Fleming, like many other pastry chefs around town, has reduced the size of her petit fours and chocolates so drastically that they are barely visible to the naked eye.

In part, the downsizing is a practical matter. Diners who have been plied with preappetizers and two rounds of dessert are not necessarily in a receptive mood when a heaping plate of mignardises arrives.

But fashion is calling the tune as well. ''It's not economics,'' said Michael Schneider, the editor in chief of Chocolatier. ''Those tidbits cost 25 cents, and there is no labor cost, because the pastry chef makes them. How tiny can you make a truffle? I'm beginning to wonder.''

Anyone looking for a little perspective might want to visit Les Sans-Culottes, a 24-year-old bistro on the Upper East Side, which knows nothing of paper-thin daikon radish slices, or what Mr. Wine calls ''the uni-tart.''